If you always put limit on everything you do, physical or anything else. It will spread into your work and into your life. There are no limits. There are only plateaus, and you must not stay there, you must go beyond them.
“If I owe Smith ten dollars and God forgives me, that doesn't pay Smith.”
“I have no trouble with my enemies. I can take care of my enemies in a fight. But my friends, my goddamned friends, they're the ones who keep me walking the floor at nights!”